


20/20 Timelines

by acoolegg



Series: 20/20 - The Soul Seer AU [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Alternate Universe - Underswap, Domestic, Domestic Fluff, F/M, Fluff, Happy, Marriage, Pain, Resets, Sad, this is a collection of one-shots, you are gonna feel things
Language: English
Status: In-Progress
Published: 2017-04-28
Updated: 2017-04-29
Packaged: 2018-10-24 16:11:24
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 3,295
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10745166
Author URL: https://archiveofourown.org/users/acoolegg/pseuds/acoolegg
Summary: A spin-off series of20/20 Sightthat focuses on G and Sans' relationship in other timelines. Every chapter is a one-shot based on a prompt/idea or an AU. If you have an idea or AU, suggest it here.On-Hiatus until my life can get itself back together and I have motivation for this again, lol. (Probably in November or something.)





	1. A Thought From Gaster

**Author's Note:**

> if you have any ideas or AUs you want me to write for, comment below plz

Gaster had told you that he had been in _multiple_ timelines. He had told you that _you and Gloria_ were constants in each timeline, and in the lives of the monsters. Yet you never once asked about them. You never asked about how the other timelines went, how everyone ended up, why he left them.

He was grateful for that. He didn't want to tell you of your countless happy times and nightmarish ends. He didn't want to tell you of the many times you and his son fell in love. He didn't want to tell you about all the lives you _could've_ had, had a different decision been made at different points in time.

That didn't mean he didn't think about the timelines, the different worlds he had witnessed. He knew of so many - he could practically write a book about them if he wasn't incorporeal.


	2. Again, Again, Again

**Summary for the Chapter:**

> Every time you came back up that mountain, Sans felt himself die a little more on the inside.

**Notes for the Chapter:**

> *looks at laptop* maybe a sad first chapter is bad  
> *looks at chapter* lol nah let's do this
> 
> if you have any ideas or AUs you want me to write for, comment below plz

In the first timeline Gaster had experienced, you had met the monsters as soon as they climbed out of the mountain. You had been taking a four-year-old Gloria early morning hiking up the trail behind your tiny house, the two of you humming and laughing as you explored. Only when she saw the monsters pouring out of the cave did you notice them.

Asgore stood firm before his people, his trident exposed so as to scare you off. You hadn't cared, though, as you approached them. Frisk tried to get the King of All Monsters to lower his weapon. Gloria let go of your hand and walked towards the towering goat man, extending her own in a handshake.

"It's nice to meet you."

There had been happy crying after that. Asgore scooped Gloria and Frisk up in a hug, cheering happily about 'humanity's change.'

From that point on, you and Gloria were with the monsters every step of the way. Tori had taken you under her wing as her assistant and your daughter once again became Frisk's best friend. Sans had been hesitant to get close to you at first, since he was accustomed to only genocide and neutral runs. He worried that he'd get too close, that'd he'd break when the world was reset again.

That changed when you confronted him about it, about his _assholish behavior_ and _nihilistic tendencies_ and how you _just wanted to be friends with him._ Sans finally gave in to his want.

Three months after the monsters were set free, you two kissed for the first time. Your lips had been soft against his teeth and your piercing kept bumping his chin. The moon made your features look extra bright. Sans felt _special_ when you told him how hauntingly beautiful he looked in the moonlight. You had looked at him like his life was precious, and he had looked at you like you were his life. His walls came tumbling down as he held you close, wrapped up together underneath the stars. He fell asleep beside you, his hand holding onto yours tightly. Sans smiled in his sleep.

He woke up in Snowdin the following morning.

Sans had sobbed quietly underneath his bed sheets, cursing Frisk for tearing his life apart again. When the child stumble out of the Ruins, sprinting for the bridge, Sans had stopped them. Anger had built up within him for having _you_ taken away.

" _Someone killed Glory. I - I'm not going to make G suffer like that. I don't want my friend to die because she's **my friend!**_ "

With that, Frisk had continued forward. They once again broke the barrier, setting all the monsters free. And, once again, Sans watched as you and Gloria approached the King of All Monsters, wonder and excitement on both of your faces. He planned on skipping the whole 'i'm not good enough to have friends' bit, and just trying to get back to where you two had been.

It seemed like fate was against that, though. After your first kiss, _every damn time_ , Gloria would die and he'd wake up in Snowdin. Over, and over, and over, and over, _and over._

He gave up going after you after one hundred of Gloria's deaths. Even then, the resets didn't stop. The little girl kept dying, just because she was friends with _monsters._ Caught in the wrong place at the wrong time - they meant to kill _Frisk_ \- a monster lover should die - he had heard every human's response to her death.

Every time the monsters walked out of the mountain to see you two walk towards them, Sans would leave. He didn't want to see your bright smile or Gloria's accepting eyes. He didn't want to see the kindness you two shared with his people.

Gaster left that timeline when it looked like the resets were never going to stop. It broke his soul to see Sans so torn up. This wasn't the timeline where he could come back into existence.


	3. Edgy

**Summary for the Chapter:**

> Even though he was pointy, he was kind.

**Notes for the Chapter:**

> lol, underfell! just thought i'd get this super sweet one out of the way. glory is OOC but i blame it on UF!sans
> 
> if you have any ideas or AUs you want me to write for, comment below plz

In another timeline, monsters were _extremely_ different from those Gaster had known. No longer beings of love and compassion, monsters were dark and frightening and full of hate towards the humans that imprisoned them. Frisk had died many times in each part of the Underground before finally showing everyone that humans had changed, at least a bit. When the barrier broke in this timeline and monsters saw the sunrise, many started to cry from happiness. Frisk held onto Toriel's hand a they led the monsters down the mountainside.

This universe's Sans was more aggressive than any other Sans, his red magic constantly manifested in his left eye showing just how angry he was with the world. You lived in Ebott City itself in this timeline, no where near the mountain. It was merely a matter of time until you two met.

Rather than meeting through Gloria and Frisk's friendship, though, you two met when he walked into your business and demanded to be told about 'that seeing bullshit.' Gaster always snickered when he remembered how you tried your damnedest to explain Seeing with getting pissed off, only to finally burst and kick Sans out.

"Don't come back into my business until you've learned some fucking manners. Stars - you're the rudest person I've ever met. The _other_ skeleton at least keeps his snarky comments to himself."

That had caused Sans to find Papyrus and interrogate him about you. This Papyrus wasn't the sweet, naive Papyrus that Gaster knew. He was an angry, powerful, _vile_ monster that spoke too harshly and had a soft spot for gentle children. Papyrus was hesitant to tell at first, but eventually came clean. He frequented your shop for soul readings and to have (he had turned an angry _red_ at the next part) tea parties with your young daughter.

(Sans had laughed. Papyrus had kicked him out.)

That had sparked his interest in you. He came back to your business, only to have you kick him out once again when he cursed in Gloria's presence. But he kept coming back. Over and over and over. Eventually, you let him back into your business. Then you let him into the top floor - your house.

Then you let him into your life. Gloria had been hesitant around him at first ("She was like this with Papyrus, as well. It's your teeth. She doesn't like pointy things.") before she grew used to crawling into his lap or having him float her around the room. Sans found out that he absolutely adored it when she'd hold his hands and smile up at him.

He and Papyrus would hang out at your house pretty often. Your friendship with the pair had not gone unnoticed by their other friends. Eventually (about a year after you met Sans) you met everyone else. Frisk and Gloria had hit it off once again. You took a while to warm up to this Toriel, but once she showed you how to make her butterscotch-cinnamon pie you opened up to her.

On _that_ evening, Sans had been in charge of watching Gloria while you ran some 'errands.' The two had grown so used to each other - as they watched TV together, Glory laid on Sans' lap while he played with her hair. "When're you gonna marry my mama?" The skeleton had jumped at the sudden question. "I know you love her and she loves you! She doesn't think I can tell but I can - she says your name when she thinks about you and it's a lot!"

Sans had sputtered, "uh, no, we're good friends--"

"That's bullshit and you know it!"

" **gloria!** "

"You say it all the time! I'm almost seven now, I can say it! Fight me, Pops!" She had that shit-eating grin on her face, and it only widened when he turned bright red. "You're blushing! You wanna be my mama's husband and my daddy!"

"Oh, does he now?" You had walked up the stairs carefully, apparently, because he hadn't heard you come up at all. You leaned against the back of your couch, your head next to his. Glory looked up at you with her wide smile. "Well, he'd have to be my boyfriend first. If that went well, then maybe he can be my husband."

Sans rubbed a hand over his red face and sighed, "i mean, i'm not _opposed_ to being your boyfriend."

"Oh, good." You stood up and went to the staircase, "Papyrus, it worked!" The skeleton tried to disappear into the couch. Gloria just grinned at him, snuggling into his ribcage.

"who all was involved in this, glor."

"DID YOU DOUBT MY PLANNING?"

"Uh, I think everyone? Alphie made some microphones for the room, Undie helped with setting up the microphones, Papy was the one that drove you over and drove Mama around, and Aunt Tori and Frisk just hung out with Mama while I interrogated you! I just had to make sure you loved my mama, and you do, so that's good. If you didn't I would've kicked you out!"

Gaster had laughed when Sans buried himself in the fluff of his jacket, his skull completely red. You kissed him for the first time that evening.

No resets ever happened in that timeline, but you never noticed him. Gaster left to find another timeline.


	4. Cute Skeleton

**Summary for the Chapter:**

> You never thought that you would fall in love with someone based on their looks, but the cute skeleton proved he was all that and more.

**Notes for the Chapter:**

> ey yo BGSunni ask and ye shall receive. (although i did have this one planned a little bit)
> 
> this is best au!g because she's a cutie. and best au!g made it really, really hard to stop. i wanted to keep these one-shots under 1000 words apiece. this one is over 1500. lol help me.
> 
> any suggestions or aus you want me to write for? leave a comment below and i'll get to it.

One of Gaster's guiltiest pleasures had been watching you and Sans in something he had called 'the Swap' timeline. At first, he had been confused about why everyone's personalities and positions were flipped, but once he had been there long enough the memories of that timeline's self came back. He was well aware of what his oldest son was like in the timeline, and he wondered how you'd deal with him. Would you fall in love with this him, or would you fall in love with this Papyrus with Sans' personality?

Your first meeting had been awkward and significantly later than most other meetings. Gloria was about ten at this time, but despite the older age she was practically the same - she was small, kind, and bursting with energy. You had brought her with you to the market to shop for that night's dinner, sending her off down the aisles to find individual pieces for dinner. You had enjoyed watching her skip down the aisles, search through the shelves thoroughly, and then look to you for a hint.

Down the baking aisle, she collided into a tall, lanky skeleton when she slipped. She fell on her butt, whereas he looked like nothing hit him. You followed after her immediately, fully prepared to apologize to the monster before he could get upset with her. He helped her up, brushing off her shoulders and making sure she stood up straight. "i have a _trip_ for you, kiddo: no runnin' in the store, alright?"

Gloria blinked up at him before nodding. "Alright! No running. I won't do it again!" She smiled up at him before turning to the cake mixes before her. She waved you back, "I got it, Ma! You said you wanted the devil's food cake mix?"

You stopped from where you were, glancing between her and the skeleton, before sighing. "Yeah, I want that one. Get the cheap-o one, please." Mister Tall-n-Lanky looked over at you, then _behind you_ , his eye sockets (somehow) widening. He opened his mouth just as you heard footsteps behind you, and you felt someone run into your back. You fell forward, at least until fingers wrapped around your wrist and pulled you back up dramatically, spinning you to face you savior with flourish.

In a dance-like dip, you stared up at the cutest skeleton you had ever seen. He had eyelights that were big and sparkling, a sweet, _sweet_ smile, and the slightest tinge of blue magic to his cheekbones. Once, in one of the rare moments he approached you in that timeline, you told Gaster about that moment in passing. _"I really hadn't ever been expecting to think 'wow, that's a cute skeleton,' but. There I was, looking at my future husband, thinking that."_

Gaster had never really seen you feel _awkward_ in any timeline, but that one was a first. Sans the helped you up after apologizing profusely and introducing himself, helping you gather all your items back into the tiny basket you carried. All the while you floundered to get your head on straight, flustered around the cute skeleton. Papyrus and Gloria both watched with barely-hidden interest as you two interacted.

Gloria, as cute and naive as she seems in many timelines, could actually be a _huge, mean jerk_ if she wanted to be. "Ma, your face is all red," she called out with a maniacal grin. "Did you," she sniggered and looked at the tall skeleton behind her, "did you _fall_ for that one?" He openly laughed at her _terrible_ joke and the shit-eating grin on her face.

You buried your face into the scarf you had been wearing, thanking Sans softly before shooting up with your grocery basket. You walked over to Gloria and, with little warning, picked her up by her middle and hoisted her to your side. You looked between the two skeletons, nodded, and walked off while your daughter mumbled about how you should've gone out with the skeleton.

At that point, you thought you were all said and done with the two skeletons. Ha, _nope._ The following week, when you came in to do actual shopping during the afternoon, the adorably cute skeleton bounced up to you again. His cheeks were far more blue than your previous encounter, and yours were significantly more red.

Sans had asked for your phone number. "I REALIZE THAT, IF WE _IMMEDIATELY_ JUMP INTO THE WHOLE DATING SCENE, WE MIGHT MISS OUT ON LEARNING ABOUT ONE ANOTHER! SO FIRST, I'D LIKE TO BECOME YOUR FRIEND. DON'T WORRY! I, THE MAGNIFICENT SANS, AM A GREAT FRIEND! I WILL TRY TO NOT OVERSHADOW YOU WITH MY GREATNESS!" You laughed at that and put your number in his phone. You were genuinely considering dating this cute skeleton.

For a couple months, you and Sans would text (and call, if you were feeling _really_ adventurous) frequently. You and Gloria would visit their adorable cottage, and Sans and Papyrus would visit your two-story business/home. The four of you became very close during your Sans regulated 'FAMILY FUN NIGHTS.'

Sans held your hand under the table one of those nights, the feeling of his gloves running over your knuckles addicting. You two began to sit closer and closer, sharing soft smiles and secret looks, gentle touches and sweet words. Both Papyrus and Gloria acted like they were none the wiser, but the pair (which grew the ideal uncle-niece relationship) conspired on ways to get you together (but only after Gloria convinced him that no, you weren't going to hurt Sans. He had been dead-set against it at first).

Your first date with Sans was at a local, authentic Mexican cuisine restaurant. You two had been debating about tacos and you had pulled in, pulled him out of your car, and sat beside him in a booth. You hadn't realized you were on a date until he stuttered out a 'I-IS THIS A DATE?' and covered his bright blue face with his bandanna. He had been so cute. You kissed him. He kissed back.

So you two started dating, much to Papyrus and Gloria's content. Nothing really changed from that - the brothers still came to your house, you and Gloria still went to their house, you still held his hand under tables and blankets - except that you could smooch him now. You could smooch him a lot.

With your solid friendship and relationship with Sans, the skeleton brothers finally introduced you to the rest of their family. The first to greet you had been a thirteen-year-old with bright red eyes that went by the name of Chara. They spoke in a soft voice and fiddled with their fingers while they struggled to put words together.

Gloria fell in love with how cute they were. ( _"Like mother, like daughter,"_ Gaster had teased.) She hung around them, peppering them with encouragement and compliments and frequently telling them how much she loved them.

After you and Gloria met Chara, your Seeing abilities came to light. The monsters readily accepted them, smiling and asking you to tell them about the souls you have seen as you grew up. Sans was uncharacteristically jealous with everyone fawning over you. He pulled you to the side and kissed you _hard._ You had melted into his touch.

Roughly a year into dating Sans, Papyrus teleported you away from your 'FAMILY FUN NIGHT.' With the fiery passion he had _exclusively_ for his big brother, he looked you in the eye and told you that you'd regret ever breaking his heart. You had looked him back and told him that you loved Sans. You loved him a lot. He had seemed pleased by your response as you two popped back into your home.

You had known something was up from that. You didn't want to get your hopes up about anything. But with Papyrus confronting you and Gloria smirking at you with that knowing glint in your eye… you had a feeling.

On the evening of Gloria's eleventh birthday, while you sat with Sans in a booth at Chuck E. Cheese, he pushed a velvet box towards you. "I COULDN'T WAIT FOR YOUR BIRTHDAY TO COME. I WAS TOO EXCITED." His face was a bright blue once again. He didn't hide, though. He smiled fondly as your daughter ran by, pulling Chara with them. He watched as you opened the box and smiled widely. "GLORIA WAS VERY HELPFUL WITH FINDING SOMETHING BEAUTIFUL. SHE KEPT SAYING, 'DAD, DAD, MA WILL LIKE THIS ONE' AND I HAD TO CONSTANTLY ASK HER, 'YOU'RE CALLING ME DAD, RIGHT?' AND SHE WAS LIKE, 'YOU'RE MY DAD, AREN'T YOU?' IT WAS VERY SWEET. THE JEWELERS KEPT GIVING US WEIRD LOOKS."

You sniggered at that, feeling tears come to your eyes. You said softly, "She loves you a lot, you know." You looked back to the ring, examining it before sliding it onto your finger.

His brow bones furrowed. "I WAS SUPPOSED TO KNEEL. THE MARRIAGE HANDBOOK SAID THAT, IN ORDER TO ASSURE THAT YOU WOULD SAY YES, I HAD TO KNEEL BEFORE YOU AND SAY YOUR WHOLE NA--"

You leaned across the table and kissed his teeth, "You did just fine without it. Of course I'll marry you, Sans. I love you."

Gloria sat beside him as you two kissed, kicking her feet happily. "I… I LOVE YOU TOO."

As cheesy as it sounds, your family lived happily ever after. But there wasn't anything Gaster could do, other than sit and watch and offer occasional advice. So he left for the next one with a sweet taste in his mouth.

**Author's Note:**

> [20/20 Sight](http://archiveofourown.org/works/7169435/chapters/16275422)   
>  [my tumblr](https://acoolegg.tumblr.com/)


End file.
